This is a regression since 4.7.1, where this example works fine (apart from the text looking either pixely or blurry during the transformation depending on whether smooth is set to true, but that's another issue).

When running the example in the qmlviewer in OpenGL mode, I see the text fine during transformation but once it is finished it shows as garbage, as illustrated by the screenshot. I'm using the 4.7 branch at 60d37c9c2f99ee1b10293c4dbc0264664dd8cad0.